Communicating with two nodes with overlapping frames

ABSTRACT

According to an example embodiment, a wireless node may determine that a first reserved retransmission frame overlaps with a second reserved transmission frame and a second reserved retransmission frame and that the second reserved transmission frame overlaps with a first reserved transmission frame and the first reserved retransmission frame. The first reserved transmission frame and the first reserved retransmission frame may be reserved for wireless communication with a first master node, and the second reserved transmission frame and the second reserved retransmission frame are reserved for wireless communication with a second master node. The wireless node may also process and acknowledge data received from the first master node during the first reserved transmission frame based on the determining, ignore data sent by the second master node during the second reserved transmission frame based on the determining, and process and acknowledge data received from the second master node during the second reserved retransmission frame based on the determining.

TECHNICAL FIELD

This description relates to wireless networking.

BACKGROUND

In wireless communication, a single wireless device or node maycommunicate with two or more wireless devices or nodes. Transmissionsbetween the wireless nodes may interfere with each other, reducingthroughput of the data. It may be desirable to reduce interference oftransmissions between the wireless nodes.

SUMMARY

The details of one or more implementations are set forth in theaccompanying drawings and the description below. Other features will beapparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a wireless node in two wireless networksaccording to an example embodiment.

FIG. 2 is a flowchart showing processes and decisions performed by thewireless node included in both of the wireless networks shown in FIG. 1according to an example embodiment.

FIG. 3A is a vertical time-sequence diagram showing negotiation ofreservation parameters according to an example embodiment.

FIG. 3B is a vertical time-sequence diagram showing negotiation ofreservation parameters according to another example embodiment.

FIG. 3C is a vertical time-sequence diagram showing negotiation ofreservation parameters according to another example embodiment.

FIG. 4 is a diagram showing slot reservations within the first wirelessnetwork and the second wireless network according to an exampleembodiment.

FIG. 5 is a diagram showing the wireless node reduce interferencebetween the first wireless network and the second wireless network bydrifting synchronization according to an example embodiment.

FIG. 6 is a diagram showing reserved transmission and reservedretransmission frames in the first wireless network and the secondwireless network according to an example embodiment.

FIG. 7 is a diagram showing reserved transmission frames in the firstwireless network and reserved transmission frames and reservedretransmission frames in the second wireless network according to anexample embodiment.

FIG. 8 is a flowchart showing a method according to an exampleembodiment.

FIG. 9 is a flowchart showing a method according to another exampleembodiment.

FIG. 10 is a flowchart showing a method according to another exampleembodiment.

FIG. 11 is a block diagram showing a wireless node according to anexample embodiment.

DETAILED DESCRIPTION

FIG. 1 is a diagram showing a wireless node 102 in wireless networks104, 106 according to an example embodiment. The wireless node 102 mayinclude, for example, an IEEE 802.15 Bluetooth device or node, an IEEE802.11 Wi-Fi or WLAN node, an IEEE 802.16 WiMAX base station, or a cellphone, according to various example embodiments. While the terminologyof Bluetooth is used herein, this disclosure may be applied to any otherwireless networking technologies, or even wired or guided technologiesin which a shared transmission medium is utilized by at least threedevices.

In the example shown in FIG. 1, the first wireless node 102 may be partof a first wireless network 104 which is shared with the second wirelessnode 108. The wireless node 102 may also be part of a second wirelessnetwork 106 which is shared with the third wireless node 110. The firstwireless node 102 may communicate time-sensitive traffic and/or datasuch as, for example, voice traffic or data to and/or from each of theother wireless nodes 108, 110. The time-sensitivity of the traffic ordata may make it unfeasible to retransmit data which are not accuratelyreceived, unless the data are retransmitted immediately after thetransmission. The wireless node 102 may be wirelessly paired or coupledwith each of the wireless nodes 108, 110. The pairing of the wirelessnode 102 with each of the wireless nodes 108, 110 in the wirelessnetworks 104, 106, respectively, is described in greater detail withrespect to FIGS. 3A, 3B, 3C below.

In establishing the pairing and/or the negotiation with either or bothof the wireless nodes 108, 110 in the wireless networks 104, 106respectively, the wireless nodes 102, 108, 110 may establish which node102, 108, 110 is the master of the respective network 104, 106 and whichnode 102, 108, 110 is a slave of the respective wireless network 104,106. In each of the wireless networks 104, 106, one node 102, 108, 110may be considered the master and one or more nodes may be considered aslave. Each network 104, 106 may have one master, and anywhere betweenone and seven slaves in a Bluetooth example, or any number of slaves,according to example embodiments. A node 102, 108, 110 may be a masterin zero or one networks, but may not be master in more than one network104, 106. A node 102, 108, 110 may be a slave in any number of networks104, 106, or up to eight networks according to example embodiments.While only two nodes 102, 108, 110 are shown in each of the wirelessnetworks 104, 106 shown in FIG. 1, any number, such as between two andeight, wireless nodes 102, 108, 110 may be included in the wirelessnetworks 104, 106, according to example embodiments.

In each of the wireless networks 104, 106, the master may control thetiming of transmissions within the network 104, 106. The networks 104,106 may, for example, utilize time division duplexing or time divisionmultiplexing to control when data is sent or received within frames.Data or frames sent from a master to a slave may be considered downlinktransmissions, whereas data or frames sent from a slave to the master ofa respective network 104, 106 may be considered uplink transmissions.The master of the respective network 104, 106 may determine the timingof the respective network 104, 106 by sending preambles which may be atthe beginning of downlink frames sent by the master. The slaves withinthe network 104, 106 may listen for the preambles and time theirlistening for, and sending of, frames accordingly. If a slave within anetwork determines that a frame is not destined for the slave, based,for example, on a destination address included in the frame not matchingthe address of the slave, the slave may sleep or power down for theremainder of the frame, and wake up or power on when the next frame isexpected. At times, the phases, clocks, or synchronizations of themasters within respective networks 104, 106 may shift which may causeframes or slots sent within one network 104, 106 to interfere with twoframes or slots in the other network 104, 106.

The wireless nodes 102, 108, 110 may utilize acknowledgements todemonstrate that frames and/or transmissions were correctly received.For example, the slaves, upon successfully receiving a downlinktransmission from their respective master during a downlink slot, maysend an acknowledgement during the following uplink slot. In an exampleembodiment, frames may include two slots: a downlink slot during whichthe master may send data to a slave within the network 104, 106 and anuplink slot during which the slave to which the proceeding downlink slotwas directed may send data to the master of its network 104, 106.

In synchronous connection (SCO), the master of a network 104, 106 maydedicate or reserve periodic frames and/or slots for certain slaves. InSCO, the master may dedicate periodic frames to a certain slave withinthe network 104, 106. For example, the master may dedicate or reserveevery third frame to a particular slave. If every third frame isdedicated to a particular slave, then that slave will always be able toreceive and/or transmit during a dedicated or reserved frame. This givespriority to that slave guaranteeing a certain amount of bandwidth ordata transmission. If a slave has frames dedicated or reserved for theslave, the slave may sleep or power down during transmission of otherframes, and wake up or power on only when the dedicated or reservedframes are scheduled, saving power.

The wireless nodes 102, 108, 110 may utilize extended synchronousconnection (eSCO), which may allow the nodes 102, 108, 110 to retransmitframes (or data included therein) which were not successfully receivedand/or acknowledged. In eSCO, the master of a particular network 104,106 may also dedicate and/or reserve retransmission frames for aparticular slave. In eSCO, the master and/or slave may also have thecapability of dedicating retransmission frames to a particular slave orreserving retransmission frames to a slave. When frames are reserved forretransmission, if the master does not receive an acknowledgment in anuplink slot subsequent to a downlink slot within a frame during whichthe master sent a transmission to the slave for which the frame isreserved, then the master may retransmit the data during the subsequentreserved retransmission frame. The retransmission frame may be directlyafter the reserved transmission frame. The master and slave maynegotiate a certain number of reserved retransmission frames, such as 0,1, or 2, which will follow the reserved transmission frames. The masterwill retransmit the data during the reserved transmission frames and/orreserved downlink retransmission slots until the master receives anacknowledgment from the slave for which the transmission andretransmission slots and/or frames are reserved, or until all of thereserved retransmission frames and/or slots have been exhausted.

FIG. 2 is a flowchart showing decisions and actions which may beperformed by a wireless node such as the wireless node 102 shown inFIG. 1. In the example shown in FIG. 2, the node 102 may pair with thesecond wireless node 108 (202). During the pairing of the wireless node102 with the second wireless node 108, the first wireless node 102 maydetermine whether the second wireless node 108 supports retransmission(204). The first wireless node 102 may determine whether the secondwireless node 108 supports retransmission based, for example on anindication by the second wireless node 108 of whether the secondwireless node supports eSCO.

After determining whether the second wireless node 108 supportsretransmission, the first wireless node 102 may negotiate reservationparameters with the second wireless node 108. The reservation parametersmay include whether any transmission frames will be reserved for thenode 102, 108 which becomes the slave, and/or whether retransmissionframes will be reserved for the node 102, 108 which becomes the slave.The negotiation of the reservation parameters may also take place aftera determination of which node 102, 108 will be the master and which node102, 108 will be the slave, or after some communications between thenodes has occurred, according to example embodiments.

Reservation parameters may include, for example, a period over whichframes will be allocated such as, for example, frames being grouped inblocks of six, which frames and/or slots will be reserved for the slave,and whether or how many retransmission frames or slots (after thereserved frames and/or slots) will be reserved for the slave. Forexample, the master and slave may negotiate a period or number of framesin a block, such as six, and which frame number among that block will bereserved for the slave. If, for example, the master and slave agreedthat the period of the block would be six frames, and that one of theframes, such as frame number 0, 1, 2, 3, 4, or 5, would be reserved tothe slave, then one out of every six frames would be reserved for theslave. Any other number of frames within a block may be agreed upon, butthe number of frames within a block must be the same throughout thegiven network 104, 106. Also, within each network each frame may bereserved for only one slave.

The above applies to negotiations where both the master and slave withina given network 104, 106 support SCO, and/or where at least one of themaster and slave in the given network 104, 106 does not support eSCO orretransmission. In an example in which both of the master and slavewithin a given network 104, 106 support eSCO or retransmission, themaster and slave may also negotiate how many retransmission frames willbe reserved for the slave after the reserved frame. The master and slavemay negotiate a number, such as 0, 1, or 2, of retransmission frameswhich will be reserved for the slave after the reserved transmissionframe.

FIGS. 3A, 3B, and 3C show examples of negotiating these reservationpatterns between the master 302 and the slave 304. While FIGS. 3A, 3B,and 3C describe negotiations with reference to the master 302 and theslave 304, these negotiations may also take place between nodes 102,108, 110 before the nodes 102, 108, 110 have determined which is themaster and which is the slave.

In the example shown in FIG. 3A, the master 302 may initiate and proposereservation parameters (306) to the slave 304. The master 302 may, forexample, propose a period or number of frames within the block, areservation number for a reserved transmission for the slave 304, and anumber of retransmission frames (which may each include amaster-to-slave downlink slot and a slave-to-master uplink slot) whichwill follow the reserved transmission frame for the slave 304. If theslave 304 is satisfied with the proposed reservation parameters, theslave 304 may send and accept reservation parameters message 308 to themaster 302, at which point the negotiation will be complete.

FIG. 3B shows an example of negotiating reservation parameters in whichthe slave 304 initiates the negotiation. In this example, the slave 304may request reservation parameters 310 to the master 304. The requestedreservation parameters may include, for example, the period or number offrames within a block, the reserved transmission slot or frame, and/orthe number of reserved retransmission frames or slots. In response toreceiving the request reservations message 310 from the slave 304, themaster 302 may send a proposed reservations parameter message 306 to theslave 304. If the master 302 agrees with the requested reservationparameters included in the message 310 sent by the slave, then theproposed reservation parameters message 306 may include the samereservation parameters as the request reservation parameters message 310sent by the slave 304 to the master 302. If the master 302 does notagree to the requested reservation parameters, then the proposedreservation parameters message 306 may include different reservationparameters then the reservation parameters included in the requestreservation parameters message 310. In response to receiving theproposed reservation parameters message 306 from the master 302, theslave 304 may send an accept reservation parameters message 308 to themaster 302, accepting the reservation parameters included in theproposed reservation parameters message 306.

FIG. 3C shows an example of negotiation over reservation parameters inwhich the slave 304 requests different parameters than those initiallyproposed by the master 302. In this example, the master 302 may initiatethe negotiation over reservation parameters by sending a proposedreservation parameters message 312 to the slave 304. In this example,the slave 304 wants to have different reservation parameters than thoseincluded in the proposed reservation parameters message 312. The slave304 will, because it requests different reservation parameters thanthose included in the proposed reservation parameters message 312, senda request reservation parameter message 310 to the master 302. Therequest reservation parameters message 310 may include differentreservation parameters than the reservation parameters included in theproposed reservation parameters message 312 sent by the master 302. Themaster 302 may receive the request reservation parameters message 310and determine whether the master 302 can accommodate the reservationparameters included in the request reservation parameters message 310.The master 302 may respond to the request reservation parameters message310 by sending a proposed reservation parameters message 306 to theslave 304. If the master 302 is able to accommodate the reservationparameters included in the request reservation parameters message 310,then the proposed reservation parameters message 306 may include thesame reservation parameters as the request reservation parametersmessage 310. If the master 302 is not able to accommodate thereservation parameters included in the request reservation parametersmessage 310, then the proposed reservation parameters message 306 mayinclude different reservation parameters then the reservation parametersincluded in the request reservation parameters message 310 and mayinclude the same parameters included in the proposed reservationparameters message 312. In response to receiving the proposedreservation parameters message 306, the slave 304 may send an acceptreservation parameters message 308 to the master 302, accepting theproposed reservation parameters included in the proposed reservationparameters message 306.

Returning to FIG. 2, if the first wireless node 102 determines that thesecond wireless node 108 does not support retransmission, then the firstwireless node 102 may request to be the master of the wireless network104 shared with the wireless node 108 (206). Becoming the master of thewireless network 104 may allow the first wireless node 102 to determinetiming and/or synchronization of transmissions, such as by controllingthe frames and/or slots within the wireless network 104. A determinationmay be made whether the second wireless node 108 allowed the firstwireless node 102 to be the master of the first wireless network 104(208).

After the determination of whether the first wireless node 102 may bethe master within the first wireless network 104, the wireless node 102may engage in data transmission and/or communication with the wirelessnode 108. The data transmission and/or communication may utilize frameswhich each include two slots, namely, a master-to-slave downlinktransmission slot followed by a slave-to-master uplink transmissionslot.

FIG. 4 is a diagram showing slots and/or frames within the firstwireless network 104 and the second wireless network 106 according to anexample embodiment. The slots and frames 400A at the top of FIG. 4 maybe used for communication in the first wireless network 104, and theslots and frames 400B at the bottom of FIG. 4 may be used forcommunication in the second wireless network 106. A frame may include apair of slots, such as the master-to-slave downlink transmission orretransmission slot 410A, 410B, paired with a slave-to-master or uplinktransmission or retransmission slot 411A, 411B.

In the master-to-slave or downlink transmission slots 410A, 412A, 414A,420A, 422A, 424A, 410B, 412B, 414B, 420B, 422B, 424B included in thefirst half of each frame, the master may send the beacon or preamble,which may be used by the slaves within the respective network 104, 106to synchronize to the master. The master-to-slave or downlink slot 410A,412A, 414A, 420A, 422A, 424A, 410B, 412B, 414B, 420B, 422B, 424B mayalso include a destination address identifying the wireless node 102,108, 110 which is the slave and which is the intended recipient of thedata included in the master-to-slave or downlink slot 410A, 412A, 414A,420A, 422A, 424A, 410B, 412B, 414B, 420B, 422B, 424B. If the destinationaddress does not identify a listening slave, then the slave may sleep orpower down until the remainder of the frame, waking or power on tolisten to the next frame, which will begin with the next master-to-slavedownlink slot 412A, 414A, 420A, 422A, 424A, 410B, 412B, 414B, 420B,422B, 424B. The master-to-slave or downlink slot 410A, 412A, 414A, 420A,422A, 424A, 410B, 412B, 414B, 420B, 422B, 424B may also include any dataintended for the slave to which the downlink or master-to-slave slot410A, 412A, 414A, 420A, 422A, 424A, 410B, 412B, 414B, 420B, 422B, 424Bis addressed or destined. The subsequent slave-to-master or uplink slot411A, 413A, 415A, 421A, 423A, 425A, 411B 413B, 415B, 421B, 423B, 425Bmay be allocated or assigned to the slave which was identified in thepreceding master-to-slave or downlink slot 410A, 412A, 414A, 420A, 422A,424A, 410B, 412B, 414B, 420B, 422B, 424B. In an example in which some ofthe frames were reserved for a particular slave, some of the frames (andthe slots included therein) may automatically be reserved and dedicatedto a particular slave. For example, if each block or period included 3frames and/or 6 slots, then if the ‘0’ frame was reserved for the slavein the first wireless network 104, then the slots 410A, 411A, 420A, 421Amay be reserved for the slave in the first wireless network 104. A slavefor which some frames are dedicated or reserved may sleep or power downduring other frames, and wake up or power on only when the framesdedicated or reserved for that slave are scheduled for transmission,thereby saving power, according to an example embodiment.

In an eSCO example, the downlink transmissions from the master to theslave which are successfully received by the slave may be acknowledgedby the slave. For example, if the data included in the master-to-slavedownlink slot 410A was successfully received by the slave, then theslave may acknowledge the successful receipt of the transmission in thesubsequent slave-to-master uplink slot 411A. Similarly, if the datatransmitted to the slave in the master-to-slave downlink slot 420A wassuccessfully received by the slave, then the slave may acknowledge thesuccessful receipt in the slave-to-master uplink slot 421A. If eitherthe master or the slave does not support retransmission, such as ifeither the master of the slave supports SCO but not eSCO, then frameswhich are not acknowledged may not be retransmitted, which may be due tothe time sensitivity of the data.

In an example in which retransmission is supported, such as when boththe master and slave support eSCO, certain frames, and the slotsincluded therein, may be reserved for retransmission. The framesreserved for retransmission may immediately follow the frames reservedfor transmission. For example, if the frames which include the slots410A, 411A, 420A, 421A are reserved for transmission, and one frame isreserved for retransmission between the first wireless node 102 and thesecond wireless node 108 within the first wireless network 104, then theframes which include the slots 412A, 413A may be reserved forretransmission in case the data included in the master-to-slave downlinkslot 410A is not acknowledged by the slave as being successfullyreceived during the slave-to-master uplink slot 411A, and the framewhich includes slots 422A, 423A may be reserved for retransmission ofdata which is not acknowledged by the slave as being successfullyreceived during the frame which include slots 420A, 421A.

For example, if the data sent by the master in the master-to-slavedownlink slot 410A is acknowledged in the slave-to-master uplink slot411A, then the data may not be retransmitted in the subsequentmaster-to-slave downlink slot 412A, and the frame which includes slots412A, 413A may not be used. However, if the slave does not acknowledgethe data sent in the master-to-slave downlink slot 410A during theslave-to-master uplink slot 411A (or the master does not receive theacknowledgment), then the master may retransmit the same data during thesubsequent master-to-slave downlink slot 412A. If the slave successfullyreceives the data during the subsequent master-to-slave downlink slot412A, then the slave may acknowledge successful receipt during theslave-to-master uplink slot 413A. However, if the data is notsuccessfully received during either the master-to-slave downlink slot410A or the master-to-slave downlink slot 412A, then the data may not beretransmitted in the case in which one frame was reserved forretransmission after each reserved transmission frame.

In an example in which two frames are reserved for retransmission foreach frame reserved for transmission, then the frames which include theslots 412A, 413A, 414A, 415A may be reserved for retransmission of datasent in slots 410A and 411A, and slots 422A, 423A, 424A, 425A may bereserved for retransmission of data transmitted in the frame whichincludes slots 420A and 421A. For example, if the master sends dataduring the master-to-slave downlink slot 410A, but the slave does notacknowledge successful receipt of the data during the slave-to-masteruplink slot 411A (or the master does not receive the acknowledgment),then the master may retransmit the data during the subsequentmaster-to-slave downlink slot 412A. If the slave still does notacknowledge successful receipt of the data during the subsequentslave-to-master uplink slot 413A (or the master does not receive theacknowledgment), then the master may retransmit the data one last timeduring the second subsequent master-to-slave downlink slot 414A. If theslave successfully receives the data during the second subsequentmaster-to-slave downlink slot 414A, then the slave may acknowledgesuccessful receipt of the data during the second subsequentslave-to-master uplink slot 415A. However, if the slave does notacknowledge successful receipt of the data during the second subsequentslave-to-master uplink slot 415A, then the master may not retransmit thedata which was initially sent during the master-to-slave downlink slot410A and was retransmitted during the subsequent master-to-slavedownlink slots 412A, 414A. While transmission and retransmission havebeen described with reference to the slots 400A in the first wirelessnetwork 104, the techniques are equally applicable to the secondwireless network 106.

Returning to FIG. 2, the wireless node 102 may pair with the thirdwireless node 110. If the first wireless node 102 was not able to becomethe master of the first wireless network 104, then the first wirelessnode 102 may follow pairing with the third wireless node 110 (210) bydetermining whether the third wireless node 110 supports retransmission(212). The first wireless node 102 may determine whether the thirdwireless node 110 supports retransmission of data during negotiationand/or pairing with the third wireless node 110. If the third wirelessnode 110 does not support retransmission, then the first wireless node102 may request to be the master of the second wireless network 106(214).

If the phases of the communications within the first network 104 and thesecond network 106 drift and/or have a phase shift or are out of phase,this may cause one frame or slot of one of the networks 104, 106 tointerfere with two of the frames or slots of the other network 104, 106.Whether the first wireless node 102 is able to correct this phasedifference or phase drift depends on whether the third wireless node 110allowed the first wireless node 102 to be the master (216) of the secondwireless network 106. The first wireless node 102 may have attempted tobecome the master of the second wireless network 106 during pairing withthe third wireless node 110 and/or may have attempted to become themaster of the second wireless network 106 after pairing and whilecommunication with the third wireless node 110 were ongoing. If thefirst wireless node was not able to become the master of either thefirst wireless network 104 or the second wireless network 106, then thefirst wireless node 102 may be unable to correct the phase difference orphase drift and communications may be lost. If the first wireless node102 was able to become the master of either the first wireless network104 or the second wireless network 106, then the first wireless node 102may correct the phase difference or the phase drift.

FIG. 5 shows is a diagram showing the first wireless node 102 reduceinterference between the first wireless network 102 and the secondwireless network 106 according to an example embodiment. In thisexample, the first wireless node 102 is master of either the secondwireless node 108 in the first wireless network 104 or the thirdwireless node 110 in the second wireless network 106, but is not masterof both the second wireless node 108 in the first wireless network 104and the third wireless node 110 in the second wireless network 106. Inthis example, the frames at the top of FIG. 5, which include slots 410A,411A, 420A, 421A, 430A, 431A, may be assigned or reserved within thefirst wireless network 104, and the frames in the bottom of FIG. 5,which include the slots 410B, 411B, 420B, 421B, 430B, 431B, may beassigned or reserved in the second wireless network 106.

In the example shown in FIG. 5, the communications between the firstwireless node 102 and the second wireless node 108 within the firstwireless network 104 may not be synchronized, and/or may be out of phasewith, the communications between the first wireless node 102 and thethird wireless node 110 within the second wireless network 110. Thecommunications between the first wireless node 102 and the secondwireless node 108 within the first wireless network 104 may be said tolead the communications between the first wireless node 102 and thethird wireless node 110 within the second wireless network 106, and/orthe communications between the first wireless node 102 and the thirdwireless node 110 within the second wireless network 106 may be said tolag the communications between the first wireless node 102 and thesecond wireless node 108 within the first wireless network 104.

The leading of communications the first wireless network 104 is shown inFIG. 5 by the phase shift 502 between the first transmission 410A in thefirst wireless network 104 before the first transmission 410B in thesecond wireless network 106. A frame which includes the slots 410A, 411Aor 420A, 421A may interfere with a frame which includes the slots 410B,411B or 420B, 421B, as well as the frame preceding the frame whichincludes the slots 410B, 411B or 420B, 421B. Similarly, a frame whichincludes the slots 410B, 411B or 420B, 421B may interfere with a framewhich includes the slots 410A, 411A or 420A, 421A, as well as a framewhich follows the frame which includes the slots 410A, 411A or 420A,421A. Thus, each frame in the wireless networks 104, 106 may interferewith two frames in the other wireless network 104, 106.

In an example in which the first wireless node 102 is the master of thethird wireless node 110 in the second wireless network 106, the firstwireless node 102 may correct the phase difference, lack ofsynchronization, and/or overlapping of frames by shifting thesynchronization or phase of transmissions with the third wireless node110 within the second wireless network 106. As discussed above, themaster of a wireless network may control the synchronization or phase oftransmissions by sending a beacon signal, such as a preamble, at thebeginning of the master-to-slave downlink slots 410B, 420B, 430B, whichserves as a reference point for the slave nodes. The first wireless node102 may, for example, advance transmissions and/or reduce the periodbetween transmissions with the third wireless node 110 within the secondwireless network 106 to reduce the phase shift or phase difference. Thefirst wireless node 102 may shift the phase or synchronizationgradually, such as within predetermined phase or synchronizationtolerances, to allow communications to continue within the secondwireless network 106. As shown in FIG. 5, the shift of the phase willreduce the phase difference from the phase 502 to the phase 504.Eventually, the phase difference will become zero or negligible as shownin the alignment between the frame which includes slots 430A, 431A andthe frame which includes slots 430B, 431B.

The wireless node 102 may also correct the synchronization or phasedifference by a phase drift if the wireless node 102 is the master inthe leading wireless network such, as the first wireless network 104shown to be leading in the example shown in FIG. 5. In the example inwhich the first wireless node 102 is the master of the second wirelessnode 108 in the first wireless network 104, which is leading the secondwireless network 106, the first wireless node 102 may delaytransmission, such as by increasing the period between transmissions ofbeacon signals and/or preambles, to correct the phase difference. Forexample, the first wireless node 102 may delay sending transmissions inthe downlink slots 410A, 420A, 430A, such as by sending the transmissionin the downlink slot 420A later than normally scheduled, but withinpredetermined tolerances. Eventually, the transmissions within the firstwireless network 104 will be in phase or synchronous with transmissionswith the second wireless network 106 as shown by the phase alignmentbetween the slot 430A and the slot 430B. With the phase alignment, eachframe sent in the first wireless network 104 will interfere with onlyone frame sent in the second wireless network 106.

Returning to FIG. 2, if the first wireless node 102 did become themaster of the first wireless network 104, the first wireless node 102may subsequently engage in communication with the second wireless node108. The first wireless node 102 may later pair with the third wirelessnode 110 (226). The first wireless node 102 may attempt to become themaster of the second wireless network 106. If the communication with thethird wireless node 110 within the second wireless network 106 has aphase or synchronization difference with the communication with thesecond wireless node 108 within the first wireless network 104, whichmay cause each one frame transmitted in each of the networks 104, 106 tointerfere with two frames transmitted in the other network 104, 106,then the first wireless node 102 may correct the phase difference basedon whether the first wireless node 102 was able to become the master ofthe second wireless network 106 (228).

If the first wireless node 102 was able to become the master of thesecond wireless network 106 either at the time of pairing with the thirdwireless node 110, or some time after pairing with the third wirelessnode 110, and the first wireless node 102 is therefore master of boththe second wireless node 108 in the first wireless network 104 and thethird wireless node 110 in the second wireless network 106, then thefirst wireless node 102 may correct any phase difference bysynchronizing the first wireless network 104 and the second wirelessnetwork 106 into one network (230). The first wireless node 102 may, forexample, bring both the second wireless node 108 and the third wirelessnode 110 into a single wireless network or piconet, of which the firstwireless node 102 is the master. If the first wireless node 102 is themaster of both the second wireless node 108 and the third wireless node110, then the wireless nodes 102, 108, 110 will be synchronized becauseall of the nodes 102, 108, 110 will be synchronized by the beaconsand/or preambles sent by the first wireless node 102.

If the first wireless node 102 was not able to become the master of thesecond wireless network 106, then the first wireless node 102 will havebecome the master of only one of the two wireless networks 104, 106. Ifthe first wireless node 102 is the master of only one of the twowireless networks 104, 106 and there is a synchronization or phasedifference between the communication with the wireless nodes 108, 110within the two wireless networks 104, 106, causing one frame transmittedin one of the networks 104, 106 to interfere with one frame transmittedin the other network 104, 106, then the first wireless node 102 maycorrect the phase difference between the first wireless network 104 andthe second wireless network 106 with a phase drift (232), as discussedabove with reference to FIG. 5.

If the first wireless node 102 determined that the second wireless node108 was able to support retransmission (204), then the first wirelessnode 102 may engage in communication with the second wireless node 108,as described with reference to FIG. 4, and may thereafter pair with thethird wireless node 110 (218). In pairing with the third wireless node110 in the second wireless network 106, the first wireless node maydetermine whether the third wireless node 110 supports retransmission(220). If the first wireless node 102 determines that the secondwireless node 108 does support retransmission, then the first wirelessnode 102 and the second wireless node 108 may negotiate reservationparameters.

The first wireless node 102 may determine whether the third wirelessnode 110 supports retransmission (220). If the third wireless node 110does support retransmission, such as because the third wireless node 110is an eSCO wireless node or supports eSCO, then all three of the nodes102, 108, 110 may support retransmission. In this situation, if thewireless node 102 may determines there is a synchronization or phasedifference between the first wireless network 104 and the secondwireless network 106, and/or whether one frame in one of the networks104, 106 overlaps with and/or interferes with two frames in the othernetwork 104, 106, such as because a synchronization or phase oftransmitting frames in the first wireless network 104 leads a phase oftransmitting frames in the second wireless network 106, then the firstwireless node 102 may correct the phase difference by ignoringtransmission slots based on the phase or synchronization difference(222). In this situation, in which there is a phase or synchronizationdifference between the first wireless network 104 and the secondwireless network 106, and all of the nodes 102, 108, 110 supportretransmission, the first wireless node 102 may accommodate the phaseshift by ignoring certain transmission slots, despite being the slave inboth wireless networks 104, 106.

FIG. 6 is a diagram showing reserved transmission and reservedretransmission frames in the first wireless network and the secondwireless network according to an example embodiment. In this example,all of the first wireless node 102, second wireless node 108, and thirdwireless node 110 support reserved retransmission frames. In thisexample, the first wireless node 102 has negotiated a reservedtransmission frame 610A, 620A, 630A and a reserved retransmission frame612A, 622A, 632A with the second wireless node 108; the first wirelessnode 102 has also negotiated a reserved transmission frame 610B, 620B,630B and a reserved retransmission frame 612B, 622B, 632B with the thirdwireless node 110. Also in this example, the first wireless node 102 maybe a slave to the second wireless node 108 in the first wireless network104, and the first wireless node 102 may be a slave to the thirdwireless node 110 in the second wireless network 106. Thus, the firstwireless node 102, second wireless node 108, and third wireless node 110may alternatively be referred to as a “slave node,” a “first masternode,” and a “second master node,” respectively.

The first wireless node 102 may accommodate transmission in the firstwireless network 104 and the second wireless network 106 despite a phaseor synchronization difference between the first wireless network 104 andthe second wireless network 106 (which causes one frame in each network104, 106 to interfere with two frames in the other network 104, 106) inthe situation in which both the first wireless network 104 and thesecond wireless network 106 support retransmission. In this example,reserved transmission and retransmission frames 600A on the top of FIG.6 are reserved within the first wireless network 104, and reservedtransmission and retransmission frames 600B for the second wirelessnetwork 106 are shown at the bottom of FIG. 6. In this example, only thereserved frames are shown and the slots within the frames may be assumedto be included in the shown frames. Frames which are not reserved ineither the first network 104 or the second network 106 are not shown inFIG. 6.

In this example, the wireless nodes 102, 108, 110 have negotiated areserved transmission frame and a single reserved retransmission framefor each transmission frame in both wireless couplings between the firstwireless node 102 and the second wireless node 108, and between thefirst wireless node 102 and the third wireless node 110. Thus, in thefirst wireless network, the reserved transmission frame 610A is followedby the reserved retransmission frame 612A, the reserved transmissionframe 620A is followed by the reserved retransmission frame 622A, andthe reserved transmission frame 630A is followed by the reservedretransmission frame 632A. Similarly, in the second wireless network,the reserved transmission frame 610B is followed by the reservedretransmission frame 612B, the reserved transmission frame 620B isfollowed by the reserved retransmission frame 622B, and the reservedtransmission frame 620B is followed by the reserved retransmission frame632B.

In the example shown in FIG. 6, the leading of the second wirelessnetwork 106 by the first wireless network 104 causes the reservedretransmission frames 612A, 622A of the first network 104 to overlapand/or interfere with both the reserved transmission frames 610B, 620Band the reserved retransmission frames 612B, 622B of the second network106. Thus, if the wireless node 102 communicates or receives during thereserved retransmission frame 612A, 622A, this may interfere with boththe reserved transmission frames 610B, 620B and the reservedretransmission frames 612B, 622B in the second wireless network 106.

Similarly, if the first wireless node 102 communicates with the thirdwireless node 110 in the second wireless network 106 during the reservedtransmission frames 610B, 620B, then the transmission frames 610B, 620Bof the second wireless network 106 may overlap and/or interfere withboth the reserved transmission frames 610A, 620A and the reservedretransmission frames 612A, 622A in the first wireless network 104. Thisoverlapping and/or interference may render communication between thefirst wireless node 102 and the second wireless node 108 within thefirst wireless network 104 difficult due to the interference by thereserved transmission frames 610B, 620B within the second wirelessnetwork 106 with both the reserved transmission frames 610A, 620A andthe reserved retransmission frames 612A, 622 within the first wirelessnetwork 104.

To allow communication in both the first wireless network 104 and thesecond wireless network 106, the first wireless node 102 may acknowledgedata included in frames successfully received and/or sent during thereserved transmission slots or frames 610A, 620A in the first wirelessnetwork. The first wireless node 102 may ignore data sent or received,and may not send data or frames itself, during the reservedretransmission frames 612A, 622A to prevent interference or overlap withthe reserved transmission frames 610B, 620B or reserved retransmissionframes 612B, 622B in the second wireless network 106. In an exampleembodiment, the first wireless node 102 may send acknowledgments duringthe reserved transmission frames 610A, 620A in the first wirelessnetwork 104 regardless of whether the data was successfully receivedduring the transmission frames 610A, 620A in the first wireless network104, to prevent the second wireless node 108 from resending the data orframe during the retransmission frames 612A, 622A.

In the second wireless network 106, the first wireless node 102 mayignore data or frames sent during reserved transmission frames 610B,620B, and may process and acknowledge frames sent and/or received duringthe reserved downlink transmissions included in the reservedtransmission frames 612B, 622B. The first wireless node 102 may not senddata during the reserved transmission frames 610B, 610B, and may senddata during the reserved retransmission frames 612B, 622B. Thus, thefirst wireless node 102 may communicate with the second wireless node108 within the first wireless network 104 only during the reservedtransmission frames 610A, 620A, and may communicate and may communicatewith the third wireless node 110 within the second wireless network 106only during the reserved retransmission frames or slots 612B, 622B.

The above description with reference to FIG. 6 has been made withreference to the first wireless network 104 leading the second wirelessnetwork 106. If drift causes this leading by the first wireless network104 to change, so that the second wireless network 106 begins to leadthe first wireless network 104 and/or the first wireless network 104begins to lag the second wireless network 106, then the first wirelessnode 102 may dynamically shift the method of selecting which of thetransmission or retransmission frames via which the wireless node 102communicates.

In this example in which the lagging has changed, which is shown by theframes 630A, 632A, 630B, 632B in the right-hand side of FIG. 6, afterdetermining that the phase or synchronization of transmitting frames inthe first wireless network 104 lags the phase or synchronization oftransmitting frames in the second wireless network 106, the firstwireless node 102 may communicate with the third wireless node 110 inthe second wireless network 106, by processing and acknowledging data orframes and sending data or frames, received during the reservedtransmission frames 630B, and may ignore data and not transmit duringthe reserved retransmission frames 632B. The acknowledgements in thesecond wireless networks 106 may be sent during the reservedtransmission frame 630B.

In this example, when the first wireless network 104 has begun to lagthe second wireless network 106, the first wireless node 102 maycommunicate with the second wireless node 108 in the first wirelessnetwork 104 by ignoring the reserved transmission frames 630A, andprocessing and acknowledging data sent during the reserve retransmissionframes 632A, and may send data only during the reserved retransmissionframes 632A. Thus, after the first wireless network 104 has begun to lagthe second wireless network 106, the first wireless node 102 maycommunicate with the second wireless node 108 in the first wirelessnetwork 104 during the reserved retransmission frame 632B and not usethe reserved transmission frame 630B. The first wireless node 102 maycommunicate with the third wireless node 110 within the first wirelessnetwork 106 during the reserved transmission frame 630B and may not useand/or ignore data sent during the reserved retransmission frame 632B.

Returning to FIG. 2, if the first wireless node 102 determines that thethird wireless node 110 does not support retransmission (220) (or if thefirst wireless node 102 determines that the third wireless node 110 doessupport retransmission (212) after determining that the second wirelessnode 108 does not support retransmission (204)), then the first wirelessnode 102 may request two retransmission slots (224) for eachtransmission slot and/or two retransmission frames for each transmissionframe with the node 108, 110 which does support retransmission. Thewireless node 102 may request two transmission slots or frames in thesituation in which one of the second wireless node 108 and the secondwireless node 110 supports retransmission and/or eSCO but the otherwireless node 108, 110 does not support retransmission and/or eSCO. Thismay occur after it has been determined that the second wireless node 108does support retransmission 204 but the third wireless node 110 does notsupport retransmission 220 and/or after determining that the secondwireless node 108 does not support retransmission 204 but the thirdwireless node 110 does support retransmission (212).

FIG. 7 is a diagram showing reserved transmission frames 710A, 710B,730A, 740A in the first wireless network 104 and reserved transmissionframes 710B, 720B, 730B and reserved retransmission frames 712B, 714B,722B, 724B, 729B, 732B, 734B in the second wireless network 106according to an example embodiment. In this example, the third wirelessnode 110 in the second wireless network 106 supports retransmission, butthe second wireless node 108 in the first wireless network 104 does notsupport retransmission. Also in this example, the first wireless node102 may be a slave to the second wireless node 108 in the first wirelessnetwork 104, and the second wireless node 102 may be a slave to thethird wireless node 110 in the second wireless network 106. Thus, thefirst wireless node 102, second wireless node 108, and third wirelessnode 110 may alternatively be referred to as a “slave node,” a “firstmaster node,” and a “second master node,” respectively.

In this example, the reserved frames 700A in the first network 104 shownin the top of FIG. 7 may be considered reserved frames in the firstnetwork 104 which does not support retransmission. The reserved frames700B in the second network 106 shown in the bottom of FIG. 7 may beframes transmitted within the second wireless network 106. Frames whichare not reserved in either the first network 104 or the second network106 are not shown in FIG. 7.

The first wireless node 102 may have negotiated two retransmissionframes or slots for every transmission slot with the third wireless node110 in the second wireless network 106 as described above with referenceto FIGS. 2 and 3. This negotiation may have occurred during pairing orafter pairing, according to example embodiments. In an example in whichthe first wireless network 104 lags the second wireless network 106, thetransmission frames 710A, 720A in the first wireless network 104 mayoverlap with and/or interfere with both the transmission frames 710B,720B and the first retransmission frames 712B, 722B of the secondwireless network 106. The reserved transmission frames 710A, 720A in thefirst wireless network 104 may each overlap with and/or interfere with areserved transmission frame 710B, 720B in the second wireless network.

In this example, the first wireless node 102 may receive, process, andacknowledge frames and/or data received from the second wireless node108 within the first wireless network 104 during the reservedtransmission frame 710A, 720A. Also in this example, the first wirelessnode 102 may ignore frames or data transmitted by the third wirelessnode 110 within the second wireless network 106 during the reservedtransmission frames 710B, 720B, and first reserved retransmission frames712B, 722B (which immediately follow the reserved transmission frames710B, 720B). The first wireless node 102 may process and acknowledgeframes or data sent, and may send data, during second retransmissionframes or slots 714B, 724B (which immediately follow the first reservedretransmission frames 712B, 722B). Thus, the first wireless node 102 maycommunicate with the second wireless node 108 within the first wirelessnetwork 104 during the reserved transmission frames 710A, 720A, and thefirst wireless node 102 may communicate with the third wireless node 110within the second wireless network 106 only during the second reservedretransmission frames 714B, 724B.

If the first wireless node 102 determines that the first wirelessnetwork 104 (which does not support retransmission) leads the secondwireless network 106, either initially or after previously determiningthe first wireless network 104 lags the second wireless network 106 andmaking the changes to communication described above, the first wirelessnode 102 may communicate with the second wireless node 108 within thefirst wireless network 104 during the reserved transmission frames 730A,730B, such as by receiving and acknowledging frames or data sent, andsending data during, reserved transmission frames 730A, 740A in thefirst wireless network 104. The first wireless node 102 may communicatewith the third wireless node 110 within the second wireless network 106only during the first reserved retransmission frame 732B, and may ignoreframes or data sent during the reserved transmission frame 730B andsecond retransmission frame 734B in the second wireless network 106, inthe example in which the first wireless network 104 leads the secondwireless network 106.

In this example in which the first wireless network 104, which does notsupport retransmission, leads the second wireless network 106, whichdoes support retransmission, the first wireless node 102 may acknowledgeframes received from the third wireless node 110 during the firstreserved retransmission frame 732B based on determining that the phaseor synchronization of the first wireless network 104 leads the phase orsynchronization of the second wireless network 106, and/or based ondetermining that the reserved transmission frames 730A, 740A in thefirst wireless network 104 interfere or overlap with both the reservedtransmission frame 730B and the second reserved retransmission frame729B, 734B in the second wireless network 106. Thus, in this example inwhich the first wireless network 104 leads the second wireless network106, the first wireless node 102 may communicate with the secondwireless node 108 during the reserve transmission frames 730A, 740Awithin the first wireless network 104, and the first wireless node 102may communicate with the third wireless node 110 within the secondwireless network 106 during the first retransmission frames 732Bimmediately following the transmission frames 730B. The transmissionframes 730B and second retransmission frames 734B within the secondwireless network 106 may not be used by the first wireless node 102,thereby avoiding interference between the first wireless network 104 andthe second wireless network 106.

FIG. 8 is a flowchart showing a method 800 according to an exampleembodiment. In this example, the method 800 may include determining, bya wireless node 102 wirelessly coupled to a first master node 108 and asecond master node 110, that a first reserved retransmission frame 612A,622A overlaps with a second reserved transmission frame 610B, 620B and asecond reserved retransmission frame 612B, 622B, and that the secondreserved transmission frame 610B, 620B overlaps with a first reservedtransmission frame 610A, 620A and the first reserved retransmissionframe 612A, 622A (802). The first reserved transmission frame 610A, 620Aand the first reserved retransmission frame 612A, 622A may be reservedfor wireless communication with the first master node 108 within thefirst wireless network 104 or piconet. The second reserved transmissionframe 610B, 620B and the second reserved retransmission frame 612B, 622Bmay be reserved for wireless communication with the second master node110 within the second wireless network 106 or piconet. The method 800may also include processing and acknowledging data received from thefirst master node 108 during the first reserved transmission frame 610A,620A based on the determining (804). The method 800 may also includeignoring data sent by the second master node 110 during the secondreserved transmission frame 610B, 620B based on the determining (806).The method 800 may also include processing and acknowledging datareceived from the second master node 110 during the second reservedretransmission frame 612B, 622B based on the determining.

In an example embodiment, the first master node 108 may comprise a firstIEEE 802.15 Bluetooth master node 108 and the second master node 110 maycomprise a second IEEE 802.15 Bluetooth master node 110.

In an example embodiment, the first master node 108 may include a firstExtended Synchronous Connections (eSCO) master node 108, and the secondmaster node 110 may include a second eSCO master node 110.

In an example embodiment, the first reserved retransmission frame 612A,622A may immediately follow the first reserved transmission frame 610A,620A, and the second reserved retransmission frame 612B, 622B mayimmediately follow the second reserved transmission frame 610B, 620B.

In an example embodiment, the method 800 may further include pairing, bythe wireless node 102, with the first master node 108, the pairing withthe first master node 108 comprising the wireless node 102unsuccessfully requesting to be master of the first master node 108. Themethod 800 may also include pairing, by the wireless node 102, with thesecond master node 110, the pairing with the second master node 110comprising the wireless node 102 unsuccessfully requesting to be masterof the second master node 110.

In an example embodiment, the method 800 may further includesubsequently determining that the first reserved transmission frame 630Aoverlaps with the second reserved transmission frame 630B and the secondreserved retransmission frame 632B, and that the second reservedretransmission frame 632B overlaps with the first reserved transmissionframe 630A and the first reserved retransmission frame 632A. The method800 may also include ignoring data sent by the first master node 108during the first reserved transmission frame 630A based on thesubsequent determining, processing and acknowledging data received fromthe first master node 108 during the first reserved retransmission frame632A based on the subsequent determining, and processing andacknowledging data received from the second master node 110 during thesecond reserved transmission frame 630B based on the subsequentdetermining.

In an example embodiment, the method 800 may further include requesting,by the wireless node 102, to be master when pairing with wireless nodeswhich do not support reserved retransmission frames.

In an example embodiment, the method 800 may further include determiningthat each frame (e.g., comprising slots 410A, 411A, 420A, 421A) viawhich the wireless node 102 communicates with a slave node, of which thewireless node is master, overlaps with two frames (such as the framescomprising the slots 410B, 411B, 420B, 421B and their respectivepreceding frames) via which the wireless node 102 communications with athird master node. The method 800 may also include drifting framesynchronization with the slave node until each frame (e.g. comprisingslots 430A, 431A) via which the wireless node 102 communicates with theslave node overlaps with only one frame (e.g. comprising slots 430B,431B) via which the wireless node 102 communicates with the third masternode, based on the determining that each frame via which the wirelessnode 102 communicates with the slave node overlaps with two frames viawhich the wireless node 102 communications with the third master node.

In an example embodiment, the method 800 may further include requesting,by the wireless node 102, to be master when pairing with a secondwireless node which does not support reserved retransmission frames,determining that each frame (e.g., comprising slots 410A, 411A, 420A,421A) via which the wireless node 102 communicates with a slave node, ofwhich the wireless node is master, overlaps with two frames (such as theframes comprising the slots 410B, 411B, 420B, 421B and their respectivepreceding frames which are not shown in FIG. 5) via which the wirelessnode 102 communications with a third master node. The method 800 mayalso include drifting frame synchronization with the slave node untileach frame (e.g. comprising slots 430A, 431A) via which the wirelessnode 102 communicates with the slave node overlaps with only one frame(e.g. comprising slots 430B, 431B) via which the wireless node 102communicates with the third master node, based on the determining thateach frame via which the wireless node 102 communicates with the slavenode overlaps with two frames via which the wireless node 102communications with the third master node.

FIG. 9 is a flowchart showing a method 900 according to an exampleembodiment. In this example, the method 900 may include unsuccessfullyrequesting to control a synchronization of transmissions between thefirst wireless node 102 and a second wireless node 108, the secondwireless node 108 not supporting reserved retransmission frames (206,902). The unsuccessfully request may include, for example a request tobe master or a role switch request which is denied by the secondwireless node 108. The method 900 may also include unsuccessfullyrequesting to control a synchronization of transmissions between thefirst wireless node 102 and a third wireless node 110 (904). The method900 may also include requesting reservation of at least two reservedretransmission frames 710B, 714B, 722B, 724B, 732B, 734B for everyreserved transmission frame 710B, 720B, 730B during communicationsbetween the first wireless node 102 and the third wireless node 110(224, 906). The wireless node 102 may request the reservation beingbased at least in part on the second wireless node 108 not supportingreserved retransmission frames, the unsuccessful request to controlsynchronization between the first wireless node 102 and the secondwireless node 108, and the unsuccessful request to control thesynchronization between the first wireless node 102 and the thirdwireless node 110.

In an example embodiment, the first wireless node 102 may comprise afirst IEEE 802.15 Bluetooth node 102, the second wireless node 108 maycomprise a second IEEE 802.15 Bluetooth node 108, and the third wirelessnode 110 may comprise a third IEEE 802.15 Bluetooth node 110.

In an example embodiment, the first and third wireless nodes 102, 110may include Extended Synchronous Connections (eSCO) nodes 102, 110, andthe second wireless node 108 may include a Synchronous Connection (SCO)node 108.

In an example embodiment, the method 900 may include the wireless node102 ignoring data transmitted during the reserved transmission frame710B, 720B and a first reserved retransmission frame 712B, 722B duringcommunication with the third wireless node 110. The method 900 may alsoinclude processing and acknowledging data received during a second orsubsequent reserved retransmission frame 714B, 724B during communicationwith the third wireless node 110.

In an example embodiment, the method 900 may also include the wirelessnode 102 requesting to be master when pairing with a wireless node whichdoes not support reserved retransmission frames.

In an example embodiment, the method 900 may also include determiningthat single frames (e.g., frames including slots 410A, 411A, 420A, 421A)for communication with a fourth wireless node, of which the wirelessnode 102 is master, overlap with two frames (e.g., frames includingslots 410B, 411B, 420B, 421B and their preceding frames which are notshown in FIG. 5) for communication with a fifth wireless node of whichthe wireless node 102 is slave. The method 900 may also include shiftingsynchronization of the frames for communication with the fourth wirelessnode until the single frames (e.g., a frame including slots 430A, 431A)for communication with the fourth wireless node each overlap with asingle frame (e.g., a frame including slots 430B, 431B) forcommunication with the fifth wireless node, based on the determiningthat the single frames for communication with a fourth wireless nodeoverlap with two frames for communication with a fifth wireless node.

In an example embodiment, the method 900 may further include thewireless node 102 requesting to be master when pairing with a fourthwireless node which does not support reserved retransmission frames. Themethod 900 may also include determining that single frames (e.g., framesincluding slots 410A, 411A, 420A, 421A) for communication with a fourthwireless node, of which the wireless node 102 is master, overlap withtwo frames (e.g., frames including slots 410B, 411B, 420B, 421B andtheir preceding frames which are not shown in FIG. 5) for communicationwith a fifth wireless node of which the wireless node 102 is slave. Themethod 900 may also include shifting synchronization of the frames forcommunication with the fourth wireless node until the single frames(e.g., a frame including slots 430A, 431A) for communication with thefourth wireless node each overlap with a single frame (e.g., a frameincluding slots 430B, 431B) for communication with the fifth wirelessnode, based on the determining that the single frames for communicationwith a fourth wireless node overlap with two frames for communicationwith a fifth wireless node.

FIG. 10 is a flowchart showing a method 1000 according to an exampleembodiment. In this example, the method 1000 may include determiningthat a second wireless node 108 does not support retransmission ofunsuccessfully received frames (204), that transmission frames 710A,720A reserved for communication with the second wireless node 108overlap with reserved transmission frames 710B, 720B and first reservedretransmission frames 712B, 720B for communication with a third wirelessnode 110, and that the third wireless node 110 supports at least tworeserved retransmission frames 712B, 714B, 722B, 724B for each reservedtransmission frame 710B, 720B (212) (1002). The method 1000 may alsoinclude ignoring frames transmitted by the third wireless node 110during the reserved transmission frame 710B, 720B and the firstretransmission frame 712B, 722B for communication with the thirdwireless node 110 based on the determining (1004). The method 1000 mayalso include processing and acknowledging frames received from the thirdwireless node 110 during a second or subsequent retransmission frame714B, 724B based on the determining (1006).

In an example embodiment, the first wireless node 102 may comprises afirst IEEE 802.15 Bluetooth node 102, the second wireless node 108 maycomprise a second IEEE 802.15 Bluetooth node 108, and the third wirelessnode 110 may comprise a third IEEE 802.15 Bluetooth node 110.

In an example embodiment, the method 1000 may also include processingand acknowledging frames received from the second wireless node 108during the transmission frames 710A, 720A reserved for communicationwith the second wireless node.

In an example embodiment, the method 1000 may also include determiningthat the transmission frames 730A, 740A reserved for communication withthe second wireless node 108 overlap with the second reservedretransmission frames 729B, 734B and the reserved transmission frames730B for communication with the third wireless node 110. The method 1000may also include ignore frames transmitted during the secondretransmission frame 729B, 734B and the transmission frame 730B reservedfor the third wireless node 110 based on the determining that thetransmission frames 730A, 740A reserved for communication with thesecond wireless node 108 overlap with the second reserved retransmissionframes 729B, 734B and the reserved transmission frames 730B forcommunication with the third wireless node 110. The method 1000 may alsoinclude processing and acknowledging frames received during the firstretransmission frame 732B reserved for communication with the thirdwireless node 110 based on the determining that the transmission frames730A, 740A reserved for communication with the second wireless node 108overlap with the second reserved retransmission frames 729B, 734B andthe reserved transmission frames 730B for communication with the thirdwireless node 110.

In an example embodiment, the method 1000 may also include the wirelessnode 102 requesting to be master when pairing with a wireless node 108which does not support reserved retransmission frames (206).

In an example embodiment, the method 1000 may also include the wirelessnode 102 determining that single frames (e.g., frames which includeslots 410A, 411A, 420A, 421A) for communication with a fourth wirelessnode, of which the wireless node 102 is master, overlap with two frames(e.g., frames which include slots 410B, 411B, 420B, 421B, and theirpreceding frames which are not shown in FIG. 5) for communication with afifth wireless node of which the wireless node 102 is slave. The method1000 may also include shifting synchronization of the frames forcommunication with the fourth wireless node until the single frames(e.g., frames which include slots 430A, 431A) for communication with thefourth wireless node each overlap with a single frame (e.g., frameswhich include slots 430B, 431B) for communication with the fifthwireless node, based on the determining that the single frames forcommunication with a fourth wireless node overlap with two frames forcommunication with a fifth wireless node.

In an example embodiment, the method 1000 may also include the wirelessnode 102 requesting to be master when pairing with a fourth wirelessnode which does not support reserved retransmission frames (208). Themethod 1000 may also include determining that single frames (e.g.,frames which include slots 410A, 411A, 420A, 421A) for communicationwith a fourth wireless node, of which the wireless node 102 is master,overlap with two frames (e.g., frames which include slots 410B, 411B,420B, 421B, and their preceding frames which are not shown in FIG. 5)for communication with a fifth wireless node of which the wireless node102 is slave. The method 1000 may also include shifting synchronizationof the frames for communication with the fourth wireless node until thesingle frames (e.g., frames which include slots 430A, 431A) forcommunication with the fourth wireless node each overlap with a singleframe (e.g., frames which include slots 430B, 431B) for communicationwith the fifth wireless node, based on the determining that the singleframes for communication with a fourth wireless node overlap with twoframes for communication with a fifth wireless node.

FIG. 1 is a block diagram of a wireless station node 1100 according toan example embodiment. The wireless station 1100 (e.g., wireless node102, 108, 110) may include, for example, an RF (radio frequency) orwireless transceiver 1102, including a transmitter to transmit signalsand a receiver to receive signals, a processor 1104 to executeinstructions or software and control transmission and receptions ofsignals, and a memory 706 to store data and/or instructions.

Processor 1104 may also make decisions or determinations, generateframes or messages for transmission, decode received frames or messagesfor further processing, and other tasks or functions described herein.Processor 1104, which may be a baseband processor, for example, maygenerate messages, packets, frames or other signals (such as thosedescribed above) for transmission via wireless transceiver 1102.Processor 1104 may control transmission of signals or messages over awireless network, and may receive signals or messages, etc., via awireless network (e.g., after being down-converted by wirelesstransceiver 1102, for example). Processor 1104 may be programmable andcapable of executing software or other instructions stored in memory oron other computer media to perform the various tasks and functionsdescribed above, such as one or more of the tasks or methods describedabove. Processor 1104 may be (or may include), for example, hardware,programmable logic, a programmable processor that executes software orfirmware, and/or any combination of these. Using other terminology,processor 1104 and transceiver 1102 together may be considered as awireless transmitter/receiver system, for example.

In addition, referring to FIG. 11, a controller (or processor) 1108 mayexecute software and instructions, and may provide overall control forthe station 1100, and may provide control for other systems not shown inFIG. 11, such as controlling input/output devices (e.g., display,keypad), and/or may execute software for one or more applications thatmay be provided on wireless station 1100, such as, for example, an emailprogram, audio/video applications, a word processor, a Voice over IPapplication, or other application or software.

In addition, a storage medium such as the memory 1106 may be providedthat includes stored instructions, which when executed by a controlleror processor may result in the processor 1104, or other controller orprocessor, and/or the wireless node 1100 performing one or more of thefunctions or tasks described above.

Implementations of the various techniques described herein may beimplemented in digital electronic circuitry, or in computer hardware,firmware, software, or in combinations of them. Implementations mayimplemented as a computer program product, i.e., a computer programtangibly embodied in an information carrier, e.g., in a machine-readablestorage device, for execution by, or to control the operation of, dataprocessing apparatus, e.g., a programmable processor, a computer, ormultiple computers. A computer program, such as the computer program(s)described above, can be written in any form of programming language,including compiled or interpreted languages, and can be deployed in anyform, including as a stand-alone program or as a module, component,subroutine, or other unit suitable for use in a computing environment. Acomputer program can be deployed to be executed on one computer or onmultiple computers at one site or distributed across multiple sites andinterconnected by a communication network.

Method steps may be performed by one or more programmable processorsexecuting a computer program to perform functions by operating on inputdata and generating output. Method steps also may be performed by, andan apparatus may be implemented as, special purpose logic circuitry,e.g., an FPGA (field programmable gate array) or an ASIC(application-specific integrated circuit).

Processors suitable for the execution of a computer program include, byway of example, both general and special purpose microprocessors, andany one or more processors of any kind of digital computer. Generally, aprocessor will receive instructions and data from a read-only memory ora random access memory or both. Elements of a computer may include atleast one processor for executing instructions and one or more memorydevices for storing instructions and data. Generally, a computer alsomay include, or be operatively coupled to receive data from or transferdata to, or both, one or more mass storage devices for storing data,e.g., magnetic, magneto-optical disks, or optical disks. Informationcarriers suitable for embodying computer program instructions and datainclude all forms of non-volatile memory, including by way of examplesemiconductor memory devices, e.g., EPROM, EEPROM, and flash memorydevices; magnetic disks, e.g., internal hard disks or removable disks;magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor andthe memory may be supplemented by, or incorporated in special purposelogic circuitry.

To provide for interaction with a user, implementations may beimplemented on a computer having a display device, e.g., a cathode raytube (CRT) or liquid crystal display (LCD) monitor, for displayinginformation to the user and a keyboard and a pointing device, e.g., amouse or a trackball, by which the user can provide input to thecomputer. Other kinds of devices can be used to provide for interactionwith a user as well; for example, feedback provided to the user can beany form of sensory feedback, e.g., visual feedback, auditory feedback,or tactile feedback; and input from the user can be received in anyform, including acoustic, speech, or tactile input.

Implementations may be implemented in a computing system that includes aback-end component, e.g., as a data server, or that includes amiddleware component, e.g., an application server, or that includes afront-end component, e.g., a client computer having a graphical userinterface or a Web browser through which a user can interact with animplementation, or any combination of such back-end, middleware, orfront-end components. Components may be interconnected by any form ormedium of digital data communication, e.g., a communication network.Examples of communication networks include a local area network (LAN)and a wide area network (WAN), e.g., the Internet.

While certain features of the described implementations have beenillustrated as described herein, many modifications, substitutions,changes and equivalents will now occur to those skilled in the art. Itis, therefore, to be understood that the appended claims are intended tocover all such modifications and changes as fall within the true spiritof the embodiments of the invention.

What is claimed is:
 1. An wireless node comprising: at least oneprocessor; and at least one computer-readable storage device, the atleast one computer-readable storage device comprisingcomputer-executable code that, when executed by the at least oneprocessor, is configured to cause the wireless node to: determine that afirst reserved retransmission frame overlaps with a second reservedtransmission frame and a second reserved retransmission frame and thatthe second reserved transmission frame overlaps with a first reservedtransmission frame and the first reserved retransmission frame, wherein:the first reserved transmission frame and the first reservedretransmission frame are reserved for wireless communication with afirst master node, and the second reserved transmission frame and thesecond reserved retransmission frame are reserved for wirelesscommunication with a second master node; process and acknowledge datareceived from the first master node during the first reservedtransmission frame based on the determining; ignore data sent by thesecond master node during the second reserved transmission frame basedon the determining; and process and acknowledge data received from thesecond master node during the second reserved retransmission frame basedon the determining.
 2. The wireless node of claim 1, wherein the firstmaster node comprises a first IEEE 802.15 Bluetooth master node and thesecond master node comprises a second IEEE 802.15 Bluetooth master node.3. The wireless node of claim 1, wherein the first reservedretransmission frame immediately follows the first reserved transmissionframe and the second reserved retransmission frame immediately followsthe second reserved transmission frame.
 4. The wireless node of claim 1,wherein the at least one processor and the at least onecomputer-readable storage device are further configured to cause thewireless node to: pair with the first master node, the pairing with thefirst master node comprising the wireless node unsuccessfully requestingto be master of the first master node; and pair with the second masternode, the pairing with the second master node comprising the wirelessnode unsuccessfully requesting to be master of the second master node.5. The wireless node of claim 1, wherein the at least one processor andthe at least one computer-readable storage device are further configuredto cause the wireless node to: subsequently determine that the firstreserved transmission frame overlaps with the second reservedtransmission frame and the second reserved retransmission frame and thatthe second reserved retransmission frames overlap with the firstreserved transmission frame and the first reserved retransmission frame;ignore data sent by the first master node during the first reservedtransmission frame based on the subsequent determining; process andacknowledge data received from the first master node during the firstreserved retransmission frame based on the subsequent determining; andprocess and acknowledge data received from the second master node duringthe second reserved transmission frame based on the subsequentdetermining.
 6. The wireless node of claim 1, wherein the at least oneprocessor and the at least one computer-readable storage device arefurther configured to cause the wireless node to request to be masterwhen pairing with wireless nodes which do not support reservedretransmission frames.
 7. The wireless node of claim 1, wherein the atleast one processor and the at least one computer-readable storagedevice are further configured to cause the wireless node to: determinethat each frame via which the wireless node communicates with a slavenode, of which the wireless node is master, overlaps with two frames viawhich the wireless node communicates with a third master node; and driftframe synchronization with the slave node until each frame via which thewireless node communicates with the slave node overlaps with only oneframe via which the wireless node communicates with the third masternode, based on the determining that each frame via which the wirelessnode communicates with the slave node overlaps with two frames via whichthe wireless node communicates with the third master node.
 8. Thewireless node of claim 1, wherein the processor and computer-readablestorage device are further configured to cause the wireless node to:request to be master when pairing with a second wireless node which doesnot support reserved retransmission frames; determine that each framevia which the wireless node communicates with the second wireless node,of which the wireless node is master, overlaps with two frames via whichthe wireless node communicates with a third master node; and drift framesynchronization with the second wireless node until each frame via whichthe wireless node communicates with the second wireless node overlapswith only one frame via which the wireless node communicates with thethird master node, based on the determining that each frame via whichthe wireless node communicates with the second wireless node overlapswith two frames via which the wireless node communicates with the thirdmaster node.
 9. A first wireless node comprising: at least oneprocessor; and at least one memory device, the at least one memorydevice comprising computer-executable code that, when executed by the atleast one processor, is configured to cause the first wireless node to:determine that: a second wireless node does not support retransmissionof unsuccessfully received frames; transmission frames reserved forcommunication with the second wireless node overlap with reservedtransmission frames and first reserved retransmission frames forcommunication with a third wireless node; and the third wireless nodesupports at least two reserved retransmission frames for each reservedtransmission frame; ignore frames transmitted by the third wireless nodeduring the reserved transmission frame and the first retransmissionframe for communication with the third wireless node based on thedetermining; and process and acknowledge frames received from the thirdwireless node during a second or subsequent retransmission frame basedon the determining.
 10. The first wireless node of claim 9, wherein theat least one processor and at least one memory device are furtherconfigured to cause the first wireless node to process and acknowledgeframes received from the second wireless node during the transmissionframes reserved for communication with the second wireless node.
 11. Thefirst wireless node of claim 9, wherein the at least one processor andthe at least one memory device are further configured to cause the firstwireless node to: determine that the transmission frames reserved forcommunication with the second wireless node overlap with the at leasttwo reserved retransmission frames and the reserved transmission framesfor communication with the third wireless node; ignore framestransmitted during the second retransmission frame and the transmissionframe reserved for the third wireless node based on the determining thatthe transmission frames reserved for communication with the secondwireless node overlap with the at least two reserved retransmissionframes and the reserved transmission frames for communication with thethird wireless node; and process and acknowledge frames received duringthe first retransmission frame reserved for communication with the thirdwireless node based on the determining that the transmission framesreserved for communication with the second wireless node overlap withthe at least two reserved retransmission frames and the reservedtransmission frames for communication with the third wireless node. 12.The first wireless node of claim 9, wherein the at least one processorand the at least one memory device are further configured to cause thefirst wireless node to request to be master when pairing with a wirelessnode which does not support reserved retransmission frames.
 13. Thefirst wireless node of claim 9, wherein the at least one processor andthe at least one memory device are further configured to cause the firstwireless node to: determine that single frames for communication with afourth wireless node, of which the first wireless node is master,overlap with two frames for communication with a fifth wireless node ofwhich the first wireless node is slave; and shift synchronization of theframes for communication with the fourth wireless node until the singleframes for communication with the fourth wireless node each overlap witha single frame for communication with the fifth wireless node, based onthe determining that the single frames for communication with a fourthwireless node overlap with two frames for communication with a fifthwireless node.
 14. The first wireless node of claim 9, wherein the atleast one processor and the at least one memory device are furtherconfigured to cause the first wireless node to: request to be masterwhen pairing with a fourth wireless node which does not support reservedretransmission frames; determine that single frames for communicationwith the fourth wireless node, of which the first wireless node ismaster, overlap with two frames for communication with a fifth wirelessnode of which the first wireless node is slave; and shiftsynchronization of the frames for communication with the fourth wirelessnode until the single frames for communication with the fourth wirelessnode each overlap with a single frame for communication with the fifthwireless node, based on the determining that the single frames forcommunication with a fourth wireless node overlap with two frames forcommunication with a fifth wireless node.
 15. At least onecomputer-readable storage device, the at least one computer-readablestorage device comprising computer-executable code that, when executedby at least one processor, is configured to cause a Bluetooth wirelessnode to: determine that each frame via which the Bluetooth wireless nodecommunicates with a Bluetooth slave node, of which the Bluetoothwireless node is master, overlaps with two frames via which theBluetooth wireless node communicates with a Bluetooth master node; andshift frame synchronization with the Bluetooth slave node until eachframe via which the Bluetooth wireless node communicates with theBluetooth slave node overlaps with only one frame via which theBluetooth wireless node communicates with the Bluetooth master node,based on the determining that each frame via which the Bluetoothwireless node communicates with the Bluetooth slave node overlaps withtwo frames via which the Bluetooth wireless node communicates with theBluetooth master node.
 16. The at least one computer-readable storagedevice of claim 15, wherein the shifting frame synchronization includesshifting frame synchronization within predetermined phase orsynchronization tolerances.
 17. The at least one computer-readablestorage device of claim 15, wherein the shifting frame synchronizationincludes delaying transmission.
 18. The at least one computer-readablestorage device of claim 15, wherein the shifting frame synchronizationincludes increasing a period between transmissions of beacon signals.19. The at least one computer-readable storage device of claim 15,wherein the shifting frame synchronization includes increasing a periodbetween transmissions of preambles.
 20. The at least onecomputer-readable storage device of claim 15, wherein the shifting framesynchronization includes increasing a period between transmissions ofIEEE 802.15 Bluetooth beacon signals or preambles.